Method of drying moist rooms, buildings, and the like



March 19, 1929. W E 1,706,199

METHOD OF DRYING MOIST ROOMS. BUTLDINGS, AND THE LIKE Filed Aug. 30, 1926 Patented Mar. 19 1929.

UNITED STATES PATENT OFFICE.

ALBERT WAGNER, or LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, JusTIzRAT DR.

moRITz MEYER, ADMINISTRATOR on THE RsTATB IN BANKRUPTCY or SAID WAG- NRR, ASSIGNOR To DEUBA DEU'I'SCHE BAuTBnTRocRNunes ARTIBNGBSBLL- SCHAFT m. B. R.,;B'HAN0VBR, GERMANY.

METHOD OF DRYING MOIST ROOMS, BUILDINGS, AND THE LIKE.

Application filed August 30, 1926, Serial No.

My invention relates toimprovements in the method of drying moist rooms, buildings and the like. As now practiced, buildings are dried by placing open fire places in the form of iron baskets in the rooms to be dried and burning therein coke or charcoal, the air for Supporting combustion being taken from the room. The consumed air is replaced either through open windows or pores of the walls. The product of the combustion, that is smoke having a high content of carbonic acid and air, rises from the fire places and flows over the moist surfaces of the Walls thus drying the Walls, the drying-action being accelerated by heat radiating from the fire place. This method is objectionable because the building is endangered by fire, and the floor is frequently spoilt near the fire place. Further, cracks are produced in the plaster of the ceiling and the walls. By consuming a part of the air contained within the room a sucking action is produced which prevents the flow of the drying gases through the walls. Further, the circulation of the air is comparatively small. By continuously heating the room the temperature is gradually raised, and after some time the air is saturated with moisture. If now hot and moist air flows over the cold surfaces of the brick-work the water is condensed on the Walls.

In a modification of the method air for supporting combustion is supplied to the fire places disposed within the room from the outv side. But also in this method a slight vacuum is produced within the rooms, because the fire places have a sucking action by reason of the upward flow of the burnt gases and the hot air. Further, the heating of the walls by radiation of the heat from the fire places is objectionable, and one fire place must be provided for each room. The'fire places must be attended to, so that the attendant must go through the rooms filled with the objectionable gases. In addition the fuel must be conveyed to the fire places through the said rooms, which is particularly objectionable in rooms located on higher floors.

The drying of a coat of plaster on a wall of masonry, or other similar backing, takes place entirely at the surface, it being necessary for the water in the interior layers to work its way to the surface by an action known as 132,636, and in Germany December 8, 1925.

diffusion where its evaporation mustbe brought-about by heat supplied usually by the air. ditions depends (1) upon the rate of diffusion of the water from the interior layers of the plaster to the surface and (2) upon the capacity of the air to take up and carryaway this water in the form of vapor.

The rate at which the water can be brought from the interior layers to the surface depends upon the material itself and especially upon the condition of the surface. .The principal factor which can be controlled here is the initial drying which should not proceed too rapidly as this may case-harden the surface and slow up the rate of diffusion.

The capacity of the air to take up and carry away moisture depends upon its relative humidity, its temperature, and its velocity over the surface. Air at any given temperature has a definite capacity for taking up or saturating itself with moisture. Ordinarily air is not found in a condition of complete saturation and the ratio between the amount of moisture which it holds at this temperature and the amount it could hold if fully saturated is known as its relative humidity. The tendency of the water at the surface of the plaster to evaporate into the air is measured by the relative humidity of this air. Hence it is essential that the relative humidity of the air surrounding the plaster be kept as low as possible.

The evaporation of the water from the surface of the plaster requires heat to supply what is known as the latent heat of evaporation. Thisheat can be most readily supplied and controlled by regulating the temperature of the air. As evaporation takes place, the air at the immediate surface of the plaster tends to become completely saturated and cooled under the action of evaporation. In order for evaporation to continue, this cooled, highly saturated air must be constantly removed from the surface and replaced by fresh, warm air of low relative humidity. It is therefore important to provide means for maintaining a constant circulation of warm, dry air continually passing over the surface. Increasing the velocity of this circulation speeds up the drying not only by providing increased heat for evaporation and capacity' The rate of drying under these con- I for carrying moisture away, but it also has the important effect of cutting down the thickness of the very thin layer of practically motionless saturated air which all damp materials hold at their surfaces and through which any evaporated moisture must diffuse in order to reach the current of drying air.

It will be seen that to secure rapid drying out of a plastered room it is necessary to maintain a constant supply of heated air of low relative humidity and a high rate of cireulation or ventilation to sweep the saturated air away from the plastered surfaces of the walls and ceilings.

Heating by temporary radiation or salamanders without forced or mechanical circulation furnishes only temperature, which without circulation soon tends to build up conditions of such extreme humidity that the rate of evaporation is rapidly slowed up. Another objection to this form of heating is that there is a great difierence of temperature .between the walls near the floor and the ceiling ofthe room due to the absence of circulation. This results in less uniform drying and a longer overall time, as the time at which painting or subsequent operations can begin is determined by the portions of the surface which are the slowest to dry.

The aging of a coat of lime bearing plaster involves both drying and a chemical change.

As applied to the wall the lime is in the form of calcium hydroxide Ga(OH) In aging, this material reacts with the carbon dioxide in the air formingealcium carbonate, CaCO and giving off Water. The rate at which this aging can be accomplished depends first on the rate at which carbon dioxide can be brought in contact with the calcium hydroxide, not only on the surface of the plaster but also throughout the entire thickness of the coat, and second on the drying out of the water formed in this reaction by means already discussed in detail under drying. The high porosity of even the solid forms of plaster base such as brick and unglazed tile,

as been thoroughly established.

The object of the improvements is to provide a method in which the said objections are obviated, and by means of which the rooms can be rapidly dried. With this object in view my invention consists in drying the rooms by means of air under pressure and at elevated temperature passed into the rooms from without. In the preferred form of the method carbonic acid is added to the said air under pressure. I have found that by thus drying the rooms any danger of fire is removed, and there is a pressure within the rooms which causes the hot air to flow through the pores of the walls thus directly removing the moisture to the outer air and effectivelydrying the inner parts of the walls, the carbonic acid added to the air causing the plaster to set Further, the air within the room is continuously held at a low degree of moisture, and there is no precipitating of condensed water on the walls.

In order that, my invention be more clearly understood two systems suitable for putting the same into effect have been illustrated in a diagrammatical way in the accompanying drawing, in which Fig. 1 is a sectional elevation showing a system in which a current of air under pressure and at elevated temperature is blown into the rooms of a building, the said air having a high content of carbonic acid, and

Fig. 2 is a similar sectional elevation showing a modification in which a part of the gases leaving the building is admitted to the fire place.

In the example shown in Fig. 1, the rooms a of the building communicate with one another through holes provided for doors, staircases and the like. T 0 one of the rooms, preferably to a ground room, air under pressure is supplied through a pipe 0 communicating with a fan 6, the intake pipe of the said fan being connected with a fire place 6 in whichcoke or other fuel is burnt. As has been indicated by the arrows the air supplied to the room under pressure is distributed all through the building, and it escapes in part through the walls and in part through window and door openings.

Thus the air within the rooms is held at a low degree of moisture or relative humidity by reason of the passage of the air from outside of the building through the fire place. The air thus passing through the fireplace produces combustion of the coke or other fuel, adapted by its combustion to produce carbonic acid and greatly increases the car bonic acid content thereof supplied to the room.. The air is thus forced into the room by the fan in suflicient volume to maintain a substantial pressure above atmospheric pressure which causes it in part to pass through the walls of the room and in part to pass through the window and door openings, thereby producing a continuous rapid circulation throughout the room, which, inaddition to the heat, increases the evaporation of the moisture from the surface of the wall and prevents the maintenance of the practically motionless film of saturated air, which otherwise would lie upon the surface of the wall and might be condensed thereupon.

With this motionless layer of saturated air removed by the circulation of the air in the room, the hot air laden with carbonic acid is enabled readily to be forced into and through the plaster of the wall and chemically to change the calcium hydroxide into calcium carbonate and also to carry the moisture which is liberated by the chemical reaction through the opposite surface of the wall to the outside air.

In the modification shown in Fig. 2 a part of the air blown into the building is removed through a pipe d and admitted to the fire place e. Thus the energy of the fan 72 is made use of for drawing the air from the ground room a, to the upper rooms of thebuilding, and the heat contained in the said air is regenerated.

I claim:

1. The method of heating and drying the room of a building, which consists in heating and drying fresh air outside of the building by causing the air to pass through a fireplace and forcing the heated air into the room continuously in suflicient volume to maintain the pressure'thereof in the room sufiiciently above atmospheric pressure to force a portion of the air through the walls and also to maintain continuously a rapid circulation of air throughout the room.

2. The method of drying the walls of a room of a building, which consists in heating and drying fresh air, and substantially increasing the carbonic acid gas content thereof by passing fresh air from outside of, the

CERTIFICATE OF Patent No. 1, 706, 199'.

buildin through a fireplace, forcing the mixture ofieated air and carbonic acid gas into the room in suflicient volume to maintain the pressure thereof in said room suificiently above atmospheric pressure to force a portion-of the mixture through the Walls and to maintain a rapid continuous circulation of the air throughout the room.

3. The method of heating and drying the room of a building, which consists in heating and drying fresh air outside of the build ing by causing the air to pass through a fireplace and forcing the heated air into the room continuously in suflicient volume to maintain the pressure thereof in the room sufficiently above atmospheric pressure to force a portion of the air through the walls and also to maintain continuously a rapid circulation of air throughout the room and returning a portion of the air supplied to the room to the fireplace.

In testimony whereof I hereunto afiix my signature.

- ALBERT WAGNER.

CORRECTION.

Granted March 19, 1929, to

ALBERT WAGNER.

It is hereby certified that the name of the assignee in the above numbered patent was erroneously written and' printed as "Deuba Deutsche Bautentrocknungs Aktiengesellschaft M. B. H., of Hanover, Germany", whereas said name should have been written and printed as "ll'euba Deutsche Bautentrocknungs-Gesellschaft M. B. H.,. of Hanover, Germany"; as shown by the records of assignments in this off ice; and that the said Letters Patent should he read with this correction there in that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 18th day of June, A. D. 1929.

(Seal) M. J. Moore, Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 1,706,199. Granted March 19, 1929, to

ALBERT WAGNER.

It is hereby certified that the name of the assignee in the above numbered patent was erroneously written and printed as "Deuba Dentsehe Eautentrocknungs Aktiengeseiisehatt Mr B. H., of Hanover, Germany", whereas said name should have been written and printed as "Deuba Deutsche Bantentrocknung's-Gesellschaft M. B. H., of Hanover, Germany", as shown by the records of assignments in this office; and that the said Letters Patent should be read with this correction there in that the same may coniorm to the record of the case in the Patent Office.

Signed and sealed this 18th day of June, A. D. 1929.

M. J. Moore,

(Seal) Acting Commissioner of Patents. 

